code: def _stu(X, **kwds):
      """Wrapper for Student-t's M-estimator"""
      return covariance_mest(X, "stu", **kwds)
  
imports: import warnings
  from functools import wraps
  import numpy
  from scipy.linalg import block_diag
  from scipy.stats import chi2
  from sklearn.covariance import oas, ledoit_wolf, fast_mcd
  from .distance import distance_mahalanobis
  from .test import is_square, is_real_type
label_desc: Use image node_id 6 for calling a global function with example usage: _stu(X) and returns: covariance_mest